The direct detection of gravitational waves about a decade ago heralded a new era of multi-messenger astronomy. The world also
subsequently witnessed the first simultaneous observation of gravitational and electromagnetic radiations from a single
astronomical event. The ongoing observations from the second-generation ground-based detectors, advanced LIGO-Virgo-KAGRA, have
delivered several key scientific discoveries. In this talk, I will provide a bird's eye view of the detection techniques behind some
of these key discoveries. In the last part, I will highlight the implications of multi-messenger observations from ultra-dense compact
objects, e.g., neutron stars on the unexplored territory of fundamental physics.